BY: NICOLE STEVENS
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Primary objective of mechanical ventilation is to
support breathing until neonates own respiratory
efforts are sufficient
First record of mechanical ventilation for a
neonate was in 1959
It has been one of the most important
breakthroughs in the history of neonatal care
Mortality from respiratory disorders has
decreased markedly after the introduction of
mechanical ventilation
But it created an increase in a new morbidity
(chronic lung disease, or, broncho pulmonary
dysplasia)
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Neonates are intubated because of 2 main
reasons: hypercapnic respiratory failure or
hypoxemia.
Hypercapnic respiratory failure is an inability
to remove CO2 by spontaneous breathing; it
is caused by hypoventilation or severe V/Q
mismatch; it causes an increase in arterial
PCO2 and a decrease in pH.
Hypoxemia is usually the result of V/Q
mismatch or a R) to L) shunt; or diffusion
abnormalities (abnormal space between
alveolus and capillaries) and hypoventilation
(apnoea)
Respiratory failure can occur because of
diseases in the lung, thorax, airway or
respiratory muscle
 Indications for assisted ventilation:
1. Respiratory acidosis (pH < 7.2, CO2 elevated,
normal is 35 - 45)
2. Hypoxemia while on 100% O2
3. Or on CPAP (8cm H20) with increasing
oxygen requirements (above 40 – 60%)
4. Severe apnoea
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Clinical manifestations:
 Increase or decrease in respiratory rate
 Increase or decrease in respiratory effort
 Periodic breathing with increase in respiratory
effort
 Apnoea
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Manual ventilation (eg. Neopuff)
Pressure controlled ventilation
Volume controlled ventilation
High freqency oscillation ventilation
High frequency jet ventilation
PIP (peak inspiratory pressure)
 Changes affect PaO2 & PaCO2 by altering the
MAP (mean airway pressure)
 Increase in PIP: increases PaO2 & decreases
PaCO2
 A high PIP should be used cautiously because
it may cause volutrauma, which can lead to
air leak and BPD
 The bigger the baby does not necessarily
mean a higher PIP requirement; requirement
is determined by lung compliance
PEEP (positive end expiratory pressure)
 Adequate PEEP prevents alveolar collapse and
maintains lung volume at the end of
expiration (maintains FRC)
 Improves V/Q matching
 Very high PEEP can cause overdistention
which puts pressure on the heart, reduces
venous return, then cardiac output, decreases
O2 transport and increases pulmonary
vascular resistance
Rate/frequency of ventilation
 Change in rate alters alveolar minute
ventilation
 High rate, low tidal volume is preferred
 Increase in rate can increase CO2 clearance
 Decrease in rate can decrease CO2 clearance
Inspiratory:Expiratory ratio
 Increase in the I:E ratio leads to an increase in
MAP
 A long inspiratory time: can increase
oxygenation, and may improve gas distribution;
but, may cause gas trapping, increased risk of
volutrauma and air leak, impaired venous return
and increase PVR.
 Neonates generally have a very short inspiratory
time eg 0.2 – 0.3 secs for a prem and slighter
more for a term infant; spend approx. 1/3 time
in inspiration and 2/3 in expiration
FiO2
 Changes alter alveolar oxygen pressure
Flow
 Minimal effects
 In general 8 – 12 litres used
 Higher flows needed to achieve shorter
inspiratory times
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Depends largely on the FiO2
Oxygenation increased with increase in MAP
MAP is a measure of the average pressure to
which the lungs are exposed
In CPAP for example: by increasing the PEEP
you can achieve an increase in oxygenation
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SIPPV (synchonised intermittent positive
pressure ventilation), sychronises and
supports all breaths made by the baby, if
baby not breathing spontaneously will deliver
breaths at the rate set.
SIMV (synchronised intermittent mandatory
ventilation), sychonises with the baby for the
mandated amount of breaths set by the
ventilator; if baby not breathing
spontaneously will deliver breaths at the rate
set; ventilator will not support extra breaths
above the set rate.
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Not available on all ventilators
Calculate by babies weight (usual starting point is
4mL/kg. Eg. 3kg baby will have a VG set at 12mLs.
Ventilator will use what PIP is required to achieve that
12mLs of volume (of air) flow into the lungs; so in
less compliant lungs more PIP will be required.
Increases or decreases in VG is usually done in
0.5mL/kg changes. Increasing VG will increase CO2
clearance. Decreasing VG will decrease CO2
clearance.
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Active inspiration and expiration.
Mean airway pressue
Frequency (5 – 50 Hz 300 – 3000 br/min)
Amplitude
Indications: reduced lung compliance, MAS,
lung hypoplasia (eg. With diaphagmatic
hernias), pneumonia, atelectasis, air leak, RDS
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Gas is ‘squirted’ into the lungs at a very high
velocity.
A conventional ventilator is always run in
tandem with the jet to generate the PEEP.
Expiration on HFJV is passive from elastic
recoil
A special ET adapter is used, it has a jet port
through which the HF jet pulses are
introduced and a pressure monitoring port
for determining the pressures
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Minimal handling; GNC 6 -8 hrly or with
proceduces
Blood gas monitoring
Hourly observations (SaO2, HR, RR set/actual,
PIP, PEEP, MAP, FiO2, VG set/acutal)
Suction PRN, mouth care
Checking of tapes (change if loose, too
moist), position of tube (visualise, measure,
check most recent CXR)
Medications, feeds
Parent counselling/education
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Administered via ETT
Compensates for surfactant deficiency and
reduces surface tension of the alveoli
Usually only administered 1 or 2 times in the
first 24 hours of ventilation.
Usually given because of high oxygen
requirements
Be mindful if not on volume guarantee, PIP’s
will likely need to be weaned quickly after
administration (because of increase in
compliance in the lungs)